This invention relates to ripening rooms in which agricultural produce is maintained in a controlled environment to precool, retard and/or regulate its ripening rate and uniformity in order to achieve an optimum condition for marketing.
In metropolitan areas, large quantities of agricultural produce is purchased in an unripe condition by wholesalers who distribute it to retail stores in a marketable state of ripeness for consumers. Most agricultural products consumed in industrialized countries have been and continue to be further developed for their ability to be stored in an unripe condition and to be ripened to a marketable state in a refrigerated supply line. Unripeness decreases damage and spoilage throughout a refrigerated chain of supply from farmers to retailers. Large refrigerated warehouses with many truckloads and sometimes trainloads of unripe produce are bought, ripened as needed for market and sold by wholesalers to take advantage of seasonal supplies and large-volume purchasing prices.
Bananas, however, are given a special ripening treatment in separate ripening rooms. The special treatment of bananas is more expensive per weight of produce but justifiable by particularly long supply seasons and high market volume. Due to relatively low retail price of bananas, minimizing cost of their separate ripening process is critical. The same ripening process could be used for lower-volume produce.
A previous ripening room for bananas is described in U.S. Pat. No. 5,041,298 granted to Wallace, et al. It employed fans at an interstitial wall at one end of a ripening room to draw refrigerated air through ventilation apertures in banana crates stacked from-end-to-end of the ripening room. From between the interstitial wall and the end of the ripening room, the air is recirculated up, over, down and back through the banana crates. Negative-pressure drawing of air through the ventilation apertures did not provide distribution of processing gases and refrigerated air as evenly and as thoroughly as positive-pressure circulation employed in this invention. A special interstitial wall and circulation area required extra floor space at high cost. Further, the Wallace device still required labor-intensive and costly use of mold-harboring tarp or blinds over ends of stacks.
Another tarp-using ripening room was described in U.S. Pat. No. 4,824,685 granted to Bianco, issued Apr. 25, 1989. Tarp or other film material was used continuously to seal off ends and tops of banana crates. Refrigerated air from sides was drawn to a negative-pressure plenum between rows of crates on pallets by suction fans at an end of the negative-pressure plenum. Then, like the Wallace device, the Bianco system also recirculated the refrigerated air from between an interstitial wall and an end of the ripening room. Most problems of the Wallace and the Bianco devices are similar, although the Wallace device provided a shorter distance for sucking air through the banana crates. The Bianco device also employed many motions and moving parts, thereby increasing costs and both initial and future maintenance requirements.